Originally Posted by Guy Jinbaiquerre
Thanks for the response, Ali. One follow-up question if you don't mind: If I put an S2 liner in my C3, would the fit be the same as a C3 Pro?
If so, that could be a good way for me to figure out if the C3 Pro will work for my head...
Yes, you can actually put either the C3 Pro or the S2 liner in your C3 to check fit. You might also consider removing that large rubber flap that closes off the vents from the inside to give you more room. You can still shut the vents from the outside and the small flaps built into the new comfort liner can complete the seal, if you ever find the need.
In all honesty, I'm not sure why Schuberth found it necessary to put that rubber flap on the inside of the helmet to begin with. It seems like it has caused more fit issues than it is worth (but did make it fun to Google "Mark of the Schuberth"). I've ridden in temperatures sub 20 degrees plenty of times and never found the need to close off the vents from the inside.
Like I mentioned earlier, if the Arai Signet Q provides the best fit for your head shape, I think you'll be unhappy with the fit of the C3 / C3 Pro in the long run.